Sorry I meant charging harness. It sprouts out of the side near the knock sensor, sometimes people have a hard time finding where it plugs into, I know I did.

 

Sephek u are correct. I don't see it. It's a jumper wire that is loomed into the emission harness, Aka engine harness. It jumps from single wire connector in front of thermostat housing to connector on charge/starter harness. It's purpose is coolant level on your gauge. If it's unplugged you'll have that lil red light for coolant on all the time

 

I posted a neater, correct and complete (I think) version in the original thread.
https://www.rx7club.com/showthread.p...ghlight=wiring
Enjoy!